Mathematica help needed; extract/take

I've got a very simple problem, but I don't really know that much code. I want to automate my calculations. The function afindminimum finds a minimum value, a. I then need that value a to continue. What I'm doing right now is copy-pasting the a to define it. But I want something that takes it out of the result for afindminimum, so that I don't have to copy-paste every time.

I can extract the second part like this:

But I want just the number, the thing after the arrow. I don't think Take or Extract or whatever are helpful here. So how then?